Personnel at a forward operating base are patrolling the perimeter after dark when they hear a muffled popping sound in the distance. Soon after, small shells begin raining down on them and there’s no clear indication where the attackers are shooting from. They’ve just been on the receiving end of a 2B25 “silent” 82mm mortar.

This might sound like some sort of unlockable upgrade in a video game, but it’s an actual weapon system that Russian special operations forces, commonly referred to as spetsnaz, began receiving in 2018. Jane’s was first to learn that the Kremlin had begun fielding the specialized mortars from an unnamed individual at Russia’s Army 2018 defense exposition in August 2018.

“The [Russian] Ministry of Defence is acquiring new towed and man-portable mortars for the land troops,” Jane’s source explained. “In particular, the special forces are slated for receiving several dozen 2B25 silenced mortars.”

The Burevestnik Institute, a subsidiary of Russia’s state-owned defense contractor UralVagonZavod (UVZ), has been working on the 2B25, also known as the Gull, since at least 2011. In 2015, the company announced plans to further improve the design and it’s not clear whether Russian spetsnaz have already been using earlier iterations.

Rostec

The 82mm 2B25 Gull mortar and its ammunition on display.

From the outside, the 30-pound mortar doesn't look out of the ordinary and it functions in the same way as many other modern types. An individual inserts the mortar bomb into the tube and then pulls a handle-shaped trigger to fire it. The shooter aims the weapon by using an optical sight and adjusting the angle of the barrel.

Where the 2B25 is special is in its 3VO35 82mm ammunition. A traditional mortar bomb has a propelling charge in its tail and troops can generally attach supplemental charges to increase its range. The detonation of these explosives forces the projectile out of the barrel and sends it down range.

The Gull’s mortar bombs keep that detonation entirely contained in the very long tail assembly. The sudden, extreme force pushes a physical piston against the base of the tube, which launches the projectile.

The video below shows how the piston-powered ammunition system works at around 1:24 in the runtime.

This means firing the 2B25 produces no flash or smoke and helps contain any residual auditory signature of firing behind the mortar bomb’s own body and the tube of the mortar itself. It’s not actually silent, but Burevestnik claims that shooting the weapon isn’t any louder than firing an AKM assault rifle with a PBS-1 sound suppressor attached, which is substantially quieter than a standard infantry mortar.

The 3VO35 mortar bomb features a high explosive projectile encased in a fragmentation layer made up of dozens of small steel balls, making it well suited to attacking troops, light vehicles, and ammunition and fuel caches out in the open. Regardless of the target set, being able to catch those targets unawares and giving them little warning to try and seek cover would only improve the 2B25’s effectiveness.

The video below shows an individual firing an AK-type rifle with a U.S.-made copy of the PBS-1.

The basic concept of using a self-contained cartridge with a piston to create “silent” isn’t new. Both the Soviets and the United States developed various small arms rounds using this principle for rifles, pistols, and even shotguns during the Cold War.

The Soviet Union, and now Russia, however, remained far more interested in the idea, especially with regards to pistols, after the United States had largely abandoned the concept. When it comes to small arms, the advantage of a piston cartridge is that it offers the benefits of a sound suppressor without having to actually use one, reducing the length and bulk of a “silent” weapon. The Soviet Union’s PSS, S4M, and MSP pistols are all extremely compact and ideal for concealed carry by special operators or intelligence agents.

The drawback to piston ammunition is that by keeping the propelling gasses contained inside the cartridge, they exert less outward force to actually move the projectile. This, in turn, typically limits the maximum effective range of the weapon system. For compact pistols that troops and covert operatives might use to quietly eliminate sentries or guard dogs or assassinate someone, all of which typically occur at extremely close ranges, this isn’t much of a problem.

For an indirect fire weapon such as a mortar, this could be more problematic. Burevestnik claims the 2B25 has a maximum range of just less than three-quarters of a mile, less than half that of many modern 60mm lightweight infantry mortars.

It does offer similar range to other ultra-compact “commando” mortars that various companies offer specifically for special operations use, such as the Czech ANTOS 60mm mortar. But those systems can be half the weight or less of the 2B25.

The Gull’s clear advantage over either type is its capability to operate with very little visual or auditory signature. It might also reduce the infrared signature of the mortar, making it even hard for opponents to spot it from the ground or the air.

This could allow spetsnaz units to easily get it within range of their target, especially at night, and then engage it quickly in a hit-and-run style attack before withdrawing to safety. The mortar and its ammunition are light enough for troops to carry on dismounted patrols, as well as during airborne and airmobile operations.

Vitaly Kuzmin

Russian special operators from the 45th Guards Independent Spetsnaz Brigade take up positions during a training exercise.

The typical rate of fire for the 2B25 is 15 rounds per minute, but troops can lob up to 30 mortar bombs every sixty seconds for a short period of time if necessary. That’s a lot of firepower to send an enemy’s way while they’re likely to be still scrambling to find out where the rounds are coming from, let alone trying to mount a counterattack.

Even if the rounds did little damage and caused few injuries to the enemy force, the attack could sap their morale and create a pervasive sense of fear that incoming mortar bombs could come at virtually any time with little warning. This might prompt an opponent to adopt a more defensive posture that requires troops to be in or near cover as often as possible, which could hamper their normal day-to-day activities.

So, while the 2B25 does have real limitations and the Russian defense industry is well known for presenting fanciful weapon concepts that have little likelihood of becoming a reality, the idea of a sound-suppressed mortar is a very real concept. It won't replace standard infantry mortars, but it may give Russia’s elite forces a way to launch devastating, or at least demoralizing, surprise attacks on their opponents before slinking away into the night.